Expanding mandrel.



'- Patented June 25, l90l.

/ VENTUR.

hzrz F. w. WITTE EXPANDING MANDREL. QAppucatm n filed Aug 31 1900) WITIV$$S.

(No Model.)

NITED STATES FREDERICK W'ILHELM lVITTE, OF CHELMSFORD, ENGLAND.

EXPANDING MANDREL.

SPECIEIfiATION forming part of Letters Patent No. 677,009, dated June 25, 1901. Application filed August 31, 1900. Serial No. 28,693. (No model.)

To all whmn it may concern/.-

Be it known that I, FREDERICK WILHELM WITTE, a citizen of the United States, residing at Chemlsford, in the county of Essex, England, have invented a certain new and useful Improvement in Expanding Mandrels, of which the following is a specification.

This invention relates to an improvement in expanding mandrels such as are used for lathes, grinding-machines, and the like where a piece of work having an opening in same has to be held for treatment on its outer surface or periphery, the object of the invention beingio produce a mandrel of this class which is simple in construction, effective, and durable and one which has no loose parts and which may be quickly adapted for a variety of sized openings.

In the accompanying drawings is illustrated one form of mandrel constructed according to my invention, Figure 1 being an elevation of same; Fig. 2, a section on lineman of Fig. 1; Fig. 3, an end elevation looking from the righthand end of Fig. 1,with the spindle in section; Fig. 4, a similar view to Fig. 1, but in plan; Figs. 5 and 6, an end and side elevation, respectively, of one of the expanding sections used in the mandrel; and Figs. 7 and 8, an end and side elevation, respectively, of another of the expanding sections.

The mandrel iscomposed of two partsa tapered spindle 1 and an expanding portion 2, capable of sliding thereon. The spindle is formed with a number of flat surfaces 6 along its length, which enables it to be readily and truly produced to the taper required, and the expanding part is formed of a number of sections 3 4, each having an exterior surface, which will form, with the total number employed, a body of the shape desired for the work the mandrel has to do. As this work is usually to fit and hold in circular holes, the segments are generally approximately segments of a circle on their exterior. These sections are preferably of two kinds-a narrow one, 3, and a wide one, 4, the latter having a head 5 at each end, in which is a groove '7, Figs. 7 and 8, while the narrow one, 3, has a slight projection 8 at each end to carry a groove 9. On the inside both the sections 3 and 4 may have fiat faces to correspond with the flat surfaces of the spindle; but I prefer to form them with angular faces 10 10, (see Figs. 5 and 7,) so as to take on the angle formed by each two flat surfaces of the spindie 1. The Width of each surface 10 both with segments 3 and 4 is the same, the difference in size in the exterior surface of the sections being obtained by the difference in the angle of the sides 11 11 and 12 12, respectively, of such segments. The heads 5 of the segments 4 also have their interior faces 13 13 in the same plane as the faces 10 10 and have their sides 14 14 at the same angle as the sides 11 11.

It will be seen that the smaller segments 3 are partly embraced or inclosed at the ends by the heads 5 of the segments 4, so that the latter serve to guide them. Each segment 3 and 4 has a groove on its interior face 15, in which is seated under contraction when the parts are assembled a split ring 16, Fig. 2, while the grooves 9 and 7 of both the segments 3 and 4 receive spring-rings 17 18, which are sprung into them, so that they exert a contractile force on the segments, the ring 16 0ffering a slight outward pressure against such springs,so that the parts may be kept together when they are removed from the spindle. Thus an expansible cage-like portion isprovided composed of segments, all of which are connected together, so that there are no loose parts. The faces 10 10 of all the segments are also tapered longitudinally with respect to the body of the segments to a taper which corresponds with that of the spindle, so that as the spindle is forced in or out of the expanding portion the exteriorsurfaces of such segments will be moved outward equally at either end.

The faces 6 of the spindle may be grooved, as shown at 20, to reduce the bearing-surface to the same width as the faces 10 of the segments and to facilitate the grinding of the spindle.

It will be understood that the exact construction of segments set out is not absolutely necessary, as other arrangements of same may be employed without departing from my invention. The spindle may also have any suitable number of flat faces instead of the arrangement shown.

I am aware that mandrels consisting of elastically-held segmental pieces carried by and capable of being expanded by a tapered spindle have been before proposed; but, so far as I am aware, none of these have been provided with means for preventing the movements of the segments longitudinally on the spindle when expanded and in use, with the result that should one or more of the segments move slightly longitudinally on the tapered spindle the Work will not be held absolutely centrally, This is prevented in my construction by the heads of the segments, which by embracing the segment neXtin order connect all the movable parts together, so that no segment can have a movement longitudinally without the others, though all are capable of expansion.

What I claim is- 1. In an expanding mandrel, and in combination, a series of segments composinga cage, ahead on each end of each alternate segment adapted to partly embrace the segment next to same and to guide it and interior tapered faces to such segments forming a tapered opening.

2. In an expanding mandrel, and in combination, aseries of segments composing a cage,

a head on each end of each alternate segment adapted to partly embrace the segment next to same and to guide it, interior tapered faces to such segments forming a tapered opening and means for elastically connecting such segments. 7

3. In an expanding mandrel and in combination, a series of segments composing a cage a head on each end of each alternate segment adapted to partly embrace the segment next to same and to guide it, interior tapered faces to such segments forming a tapered opening, a spring-wire surrounding each end of such segments and elastically connecting same and a spring-Wire located inside said segments to expand same slightly against the other Wires so as to hold the parts together.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

FREDERICK 'ILIIELM WI'lTll.

Vitnesses:

ALLEN PARRY J ONES,

GEORGE ISAAC BRIDGES. 

